As a large-capacity nonvolatile memory, a two-terminal resistive random access memory has been actively developed to replace a floating-gate-type NAND flash memory of the related art. This type of memory enables a low-voltage/low-current operation, high speed switching, and miniaturization and high integration of memory cells.
In a large-capacity memory array, a large number of metal wirings, called bit lines and word lines, are arranged to intersect each other, and a memory cell is formed at each intersection of the bit lines and the word lines. Writing to one memory cell is performed by applying a voltage to the bit line BL and the word line WL, which are connected to the cell.